Detection of hetero-proteins-mesoporous silica assembly by BRET.

The assembly of a hetero-protein (Renilla reniformis luciferase (Rluc) and a green fluorescence protein (sGFP)) encapsulated in folded-sheet mesoporous material with 7.1 nm pore diameter (FSM7.1), which was used for studying protein-protein interactions in pores of mesoporous silica, has been confirmed by the detection of bioluminescence resonance energy transfers (BRET).

Formation of cage-like hollow spherical silica via a mesoporous structure by calcination of lysozyme-silica hybrid particles.

Calcination of lysozyme-silica hybrid hollow particles gives novel cage-like hollow spherical silicas with differently patterned through-holes on their shell structure.

Encapsulation of hemoglobin in mesoporous silica (FSM)-enhanced thermal stability and resistance to denaturants.

Hemoblogin (Hb), which is a typical oligomeric protein, was introduced into the pores of mesoporous silica (FSM: folded-sheet mesoporous material) that had a diameter of 7.5 nm. Soret CD spectra of Hb-FSM-7.5 conjugates showed a peak that was identical to that of free Hb. This suggests that Hb retained its highly ordered structure in the mesoporous silica. In addition, the UV-visible absorption spectrum showed that Hb had an increased resistance to heat denaturation in the silica. Even after heat treatment at 85 degrees C, Hb-FSM-7.5 retained its ligand-binding activity. The stability of Hb-FSM-7.5 was examined further by measuring its peroxidase-like activity. Encapsulation of Hb resulted in the retention of activity in the presence of high NaCl or Gdn-HCl levels. This suggests that encapsulation prevented dissociation and denaturing. Thus, it seems that the mesopores created a favorable environment for the oligomeric protein to perform its function, even under harsh conditions.

Synthesis of protein-silica hybrid hollow particles through the combination of protein catalysts and sonochemical treatment.

Hollow spherical particles with protein-silica hybrid shell structures have been synthesized through a combination of the catalytic activity of the protein and sonochemical treatment; the morphologies of the particles were controlled by varying the protein concentration.

A method for the molecular imprinting of hemoglobin on silica surfaces using silanes.

A new molecular imprinting technique using covalently immobilized hemoglobin (Hb) is described for creating Hb-specific recognition cavities on silica. Two kinds of organic silane (3-aminopropyltrimethoxysilane: APTMS, and trimethoxypropylsilane: TMPS) were polymerized on a surface of porous silica after the Hb template was covalently immobilized by forming imine bonds, and their influence was analyzed. The results showed that not only the silane amount but also the relative proportions play an important role in protein imprinting. Pore size distribution on Hb imprinted silica was determined by nitrogen adsorption/desorption after removing the template Hb. The Hb-imprinted silica using covalently immobilized Hb (MIPi) as a template proved superior to silica using free Hb (MIPf) regarding displacement of template Hb, and selective re-adsorption as compared with other non-template proteins. The results suggested the capacity for selective adsorption of MIPi to be not only based on the isoelectric point (pI) and protein molecular weight, but also the characteristics of protein recognition cavities imprinted on base silica.